Rust preventive compositions



Deci17, 1957 R. A. WESTLUND, JR., ETAL 2,816,

RUST PREVENTIVE COMPOSITIONS Filed March 28, 1955 2 Sheets-Sheet 1 PENETRATION (MM/IO) AT rm m 0 IO 20 5O 4O 5O 6O 70 PER OfIIT WAX A III OOIIPOSITIOII FIG-I nor A. wssnunv, JR. MICHAEL J. FUREY INVENTORSI BY X -Z Q ATTORNEY Dec. 17, 1957 R. A. WESTLUND, JR., ETAL 2,816,842

RUST PREVENTIVE COMPOSITIONS 2 Sheets-Sheet 2 Filed March 28, 1955 w at 15w & E6

was .3 g s EEEExE 25 mvmrons I ROY A. WESTLUND, JR.

MICHAEL J. FUREY BY K 5 ATTORNEY United States Patent 'RUSTPREVENTIVE COBIPOSITIGNS Roy A. Westlun'd, J11, Linden and Michael JJFurey, Granted; N '..I., :assignors to Esso Research and Enginneeringi-Company, a corporation of. Delaware Application Mai-"ch28,"1955, Serial No.f497,0'68

.zztciaimsc1. 106-14) "Thislinvention relates to rust preventivecompositions and moreparticula'rly relates to hot-dip. rust. preventive Compositions .which. contain ,mineral. oil, wax and metal soap, the. compositions. being. substantially.v free from flow antemperatures below. about 130 F. .Theinventionalso relates tov methods for.protecting-metal.objects from corrojsion. using. such compositions.

Hot-diprust preventive. compositions varenusedto protect metallic surfaces from. corrosion undera variety oficonditions. (Such compositions are particularly useful forpreventing the rusting of ferrous metalobjects. The use of such compositions protects metallic surfaces from humidity, rain sea water and the like. The. advantage. of-hot-dip rust preventives over,.forx example, solvent-type rustipreventiv'e compositions is that afterthepart to beprotected is coated, it can be: packaged immediately with essentiallynodelay for drying. Also, there .is no fire hazardfrornv solvents. In addition,the protective films. of hot-dip. rust preventive compositions are soft and thus do not readily chip or flake oflito leave metalparts exposed if thefilm-is. Instead, the. soft 'film will vheal .it-.

accidentally struck. selfl Also,.since the film is..soft,.any film notremove'd from metal parts, such. as from bearings and the=like,fdoes.

not interfere with subsequent lubrication.

Hot-dip rustpreventives of various consistenc-iesmay be prepared. Harder coatings-generally give better proa tection and are used to protect metal, parts in exposed conditions, outdoor or semi-sheltered. Softer-coatings have the advantage that they are more easily removed while at {the same timeproviding only slightly less ,protection thanthe harder coating. .The softer products are ,particu-.

larly useful for protective shed storage or for preservation of metal parts which are .to be packaged.

Hot-dip rust preventive compositions have been .prepared heretofore using a blend of a heavy mineral oil and wax. However, in general such rust preventive compositionsEhve had to be made relativelyhard (that is, having an A.S.'- T. M. penetration below about 200 mm./1O at 77 Fl to prevent their flow from metal surfaces. These hard lcomposition shavebeen diflicu'ltto apply and remove from metal surfaces. Rust preventive compositions (prepared from oil and wax) .of a softer consistency, that is, having an *AzdS. T. -M. penetration above about .200 mot/.10

at 77 F. have not been practical heretofore since they have had a low melting point and have also tendedto. flow at'temperatures above about 100 F. Since-a large amountsof metal soaps of high molecular weight fatty.

acids toan oil-wax base rust preventive composition impart s'to thecompositicn excellent resistance to flow at all ice temperatures below about F. The addition of these metal soaps to the oil-wax base does not harden the composition and, in fact, actually softens the composition slightly. The addition of these metal soaps is also advantageous since .it permits the use of additional wax and thus further enhances the anti-flow properties of the composition.

T he rustvpreventive compositions of this invention comprise a majorproportion of a heavy mineral oil, about 8 to 30% by weight, based on total composition, of microcrystalline wax and about 0.1 to 2% by weight, based on the total composition, of metal soap of high molecular weight fatty acid, the total composition having an A. -'S. T. M. penetration of about 200 to 325 mm.'/10 at 77 FJand being substantially free from flow at temperatures below about 130 F. The properties of the rust preventive compositions of this invention may be further enhanced bytheatiditiou of minor amounts of additives such as corrosion inhibitors, oxidation inhibitors and the like.

The :adva'nt'ages' of the present invention will be more fully understood-by-r'eference to the attached drawingsof which Fig. '1 is a graph showing the relationship between the A.' S. T. M. penetration of wax-oil base rust preventive compositions and the metal soap content thereof and Fig. 2 is a graph showing the relationship between A. 8. T. -M. penetration, flow temperature and the metal soap content 'wax-oil base rust preventive compositions.

:Fig. 1 shows that the addition of minor amounts of metal soaps generally increases the A. S. T. M. penetration of 'wax-oil "base rust preventive compositions. Fig.2 shows that wax-oilbase rust preventive compositions hav-' ing an A. S. TQM. penetration of about 200 to 325 and being resistantto flow at temperatures below 130 can be prepared iutilizing minor amounts of metal soaps.

THE HEAVY MINERAL OIL The -heavy mineral oils useful in the present invention in general have an S. U. S. viscosity at 210 in-the range ofabout 100 to SOD-seconds. Preferred mineraloils have an S. U. S. viscosity at 210 F.-of about to '300fsec on'cls; Mineral oils having lowerviscosities are undesirable -because they tend to volatilize at temperaturesof about 170 to 200 R, which temperatures are'empl'oyed during the application of the rust;preventive compositions to metal -objects.- In addition, mineral oils having a -vis-* cosity -below 100 seconds have an undesirable effect upon. the fiowproperties-of the rust preventive composition.

The-preferred-heavy mineral oils are those having ;a pour-point below'about 30 Such 'mineral oils may be fractionsx-from low cold test crude oils which contain onlysmall amounts of naturally occurring wax. Such mineral-oils mayalso -be-obtained from waxy crude oils lay-removing essentially allot the wax therefrom by a dewaxing :step such as solvent (MEK, propane, 'etcr) dewaxing, plate and frame pressing and the --like. Such heavy mineral oils are preferred since they are-essentially free=of low melting point wax, particularly Waxesmeltinga below-about 130 1 THE WAX The waxes usefdl in this invention are high melting point 'waxes having a melting point in the range "of about to 210 F; Such 'waxes are known 'in the "art as: microcrystallin'e waxes and are'obtained as a by product v from #the de'Waxing-of 'heavy mineral oils -such as cylinder oils and bright-stocks. ably have a melting point-of about to 200 F.

form an oil-Wax.base-for-therust preventive compositions.

ofthisinvention. It will be understood,however that a) it is within the scope of this invention to utilize naturallyoccurring waxy oils which have an S. U. S. viscosity at 210 F. of about 100 to 500 seconds which contain the proper amount (about 8 to 30% by weight) of these microcrystalline waxes and which are essentially free of lower melting point waxes, particularly those melting below about 130 F. Also, if desired, the microcrystalline wax. may be added in the form of a petrolatum, that is, a wax containing a relatively high proportion of oil, such as 10% to 60% by weight of oil, and 90% to 40% by Weight of microcrystalline wax. The preferred microcrystalline waxes are commercial waxes containing less than about 5%, and preferably less than about 2%, by weight of oil.

THE METAL SOAPS The soaps useful in this invention are those of the grease-forming metals and those of high molecular weight fatty acids. Preferably the metals are those selected from the group consisting of alkali metals, alkaline earth. metals and aluminum. Specific examples of such metals. include sodium, potassium, lithium, strontium, calcium, barium, magnesium and aluminum. It will be understood that two or more of these metals may be employed. in the same rust preventive composition if desired. A particularly preferred rust preventive composition contains a mixture of lithium and calcium soaps.

The high molecular weight fatty acids preferably contain about 12 to 22 carbon atoms per molecule and even more preferably contain about 14 to 18 carbon atoms per molecule. These fatty acids may be derived from saturated or unsaturated naturally-occurring or synthetic fatty materials. The fatty acids normally used in the manufacture of greases may be employed in this invention, such as stearic, hydroxystearic, dihydroxystearic, polyhydroxystearic. oleic, linoleic, ricinoleic, myristic, palmitic, hydrogenated fish oil acids, tallow acids. etc.

Specific examples of metal soaps useful in this invention include aluminum stearate, mixed lithium and calcium soaps of tallow acids, lithium stearate, calcium stearate, barium stearate, sodium stearate, potassium stearate, lithium soaps of cottonseed fattv acids, calcium soaps of cottonseed fatty acids. mixed lithium and calcium soaps of cottonseed fatty acids, and the like.

The metal soaps may be added as such to the rust preventivecompositions of this invention or they may be prepared. as in grease making, in a lubricating oil and the resultant grease may be added to the rust preventive com positions of this invention in a concentration to give the desired proportion of soap in the rust preventive compositions. For example, the soaps of this invention may be prepared in lubricating oils to give greases containing about 5 to 50% by weight of the soap constituent. In this case, conventional grease-making procedures may be employed to prepare such greases. For example, about half of the lubricating oil, preferably a mineral lubricating oil, is added together with the fatty acids to a grease-making kettle and the metal may be added in the form of a basic reacting compound, such as a hydroxide or oxide, in approximately theoretical amounts (based on the amount of fatty acid) to the grease kettle to neutralize the acids. The composition may then be heated to an elevated temperature above about 212 R, such as 300 to 500 F., the remainder of the lubricating oil added and the grease cooled. Such grease-making procedures are well known in the art and need not be discussed further herein.

As stated heretofore, a particularly preferred metal soap useful in this invention is a combination of lithium and calcium soaps of high molecular weight fatty acids. Such a combination containing in the range of about 2:1 to 8:1 and preferably in the range of about 3:1 to 5:1 moles of lithium soap to moles of calcium soap are particularly preferred. Such soaps may be conveniently prepared in the presence of a mineral lubricating oil sufiicient to give a final soap content in the resultant grease of about 5 to 50 wt. percent, preferably about 6 to 20 wt.

percent. These greases containing the lithium-calcium :soaps are preferably prepared utilizing dehydration temperatures in the range of about 220 to 320 F.

THE RUST PREVENTIVE COMPOSITIONS The rust preventive compositions of this invention comprise a major proportion of a heavy mineral oil, about 8 to 30% by weight, based on the total composition, of microcrystalline wax and about 0.1 to 2% by weight, based on the total composition, of metal soap of high molecular weight fatty acid. These compositions should have an A. S. T. M. penetration (A. S. T. M. designation D937-49T) of about 200 to 325 mm./ 10 at 77 F. These limits are required to produce a composition that is soft enough to be applied easily even by brush and also to be easily removed. The composition should also have a melting point above about F. to assure that it will give good protection at elevated temperatures. In addition the composition should be substantially free from flow at all temperatures below about 130 P. so as to also assure satisfactory performance of the compositions at elevated temperatures. Since metal parts located in semisheltered or sheltered shed storage or packaged metal parts in transit can reach temperatures as high as 130 F., it is essential that the rust preventive composition must not melt nor flow from such metal parts at such temperatures. Preferred compositions of this invention contain about 60 to 90% by weight of the heavy mineral oil, about 10 to 25% by weight of the microcrystalline wax and about 0.2 to 1% by weight of the metal soap. The various ingredients may be blended together simply by heating them to a temperature of about 170 to 200 F. with stirring.

In addition to the oil, wax and soap, other materials such as dyes, e. g. fiuoroescein; oxidation inhibitors, e. g. phenyl alpha naphthylamine; and the like may be added in minor amounts to the compositions of the present in vention. Although the oil-wax-soap blends of this invention provide physical protection against rusting and the soap serves as a rust inhibitor, the preferred rust preventive compositions of this invention contain a small amount, about 0.1 to 10%, and preferably about 2 to 6% by weight based on the total composition, of additional rust inhibitor such as calcium petroleum sulfonate, barium petroleum sulfonate, sodium petroleum sulfonate, calcium alkyl benzene sulfonate, barium alkyl benzene sulfonate, sodium alkyl benzene sulfonate, sorbitan monooleate, glycerol monooleate, degras and the like or mixtures thereof so as to further improve the rust preventive properties of the total composition.

An example of a particularly preferred hot-dip rust preventive composition of this invention has the following formulation:

Wt. Percent, Ingredient Based on Tot Composition Mineral Oil (-300 S. U. S. at 210 F.) 70.0 to 80.0 Micro. Wax (-200 F. M. P.) 12.0 to 18.0 Metal Soaps. 0.2 to 0.5 Calcium Sulfnnate 2.0 to 4.0 Phenyl a-naphthylamine 0.1 to 1.0

position may be applied by brushing, swabbing or other,

equivalent means at temperatures above about 60 F.

The invention will be more fully understood by reference to the following examples. It is pointed out, however.

at the exa plese g ven. :torv the .pu pos of. illustration only and are nottobeconstruedas limiting vthe .scopeof the, present invention in. any way.

Example I 5 Anuniber Of-dififHLOi1eW3XbflSS were-prepared using aheavy mineral oiland anumber of different waxes. The oil, hereinafter referredeto. as ,thebase oil, hadyarrS; U, S. viscosity at 210. F..of about 200,.and a pour-point of about F. ,The .base oil was derivedfrornpa low:coldtest Coastal crude oil. which was essentially free from wax constituents. The. following. waxes ,were. utilized injthe preparation of the oil-wax;.b ase s:

Wax A.This wax is a further refinement of. wax B whichhas been deoiled. andrrecrystallized to eliminate the lower melting pointwvaxes. It; has-. tha-following properties: melting point,; about.175, F.; pene,trationv (ASTM D- about .oil contenLabout; 1.2%

Wax B.-This vwax is,.aupetrolatum prepared. from a paraffiuic crude. It is obtained by deasphalting and-solvent dewaxing the residuum from; a.crude:distillation, and has the. following properties;:melting point, about 164 F.; penetration (ASTM D-5), about-90; ,oil content, about Wax C.This waxis: asQ-called -.tank.bottom.wax. ob tained from Mid-Continent crudes. .When crude oil -is pumped fromthe ground andallowed to. stand in field tanks a .certain;.,amount .of resins, asphaltenes,- and; high melting point ..,waxes known: loosely 5 asftankrbottoms precipitate from the crude. This. .wax. is :preparedby .dehydrating, deasphaltingand- .recrystallizing ,this mixture to remove asphaltenes, resins, and.lowermelting-point waxes. This wax has the,following general..properties:. melting point, about 185 F.; .penet-ratio n (AS T M. D -S), about 0 12; oil content, about 1.1%.

Wax. D.-. This .wax is anothertype, of= microcrystalline wax similar to .wax, A. .It is, prepared, from Mid- Conw tinent crudes by deasphalting and dewaxing the residuum from a distillation process. This-firstrproductiis then further deoiledandsolvent.dewaxed-to remove the lower melting point waxes leaving a product with "the following properties: --melting --point, about 190 penetration (ASTM D'5 about-4; oil con-tent, 1 about 1.0

Wax E.Thiswax is also'a so-called tank bottom-wax from Mid-Continent crudes similar-to the described-in wax D and prepared in the same general manner. The dehydrating, deasphalting and recrystallization conditions were varied to give a wax having a slightly lower penetration and slightly higher melting point. The general properties of the wax are: melting point, about 195 F.; penetration (ASTM D-5), about 7; oil content, about 1.0%.

The following oil-wax bases which consisted of the designated wax and the base oil were prepared and evaluated for their A. S. T. M. penetration, melting point and flow properties at 130 F. as shown in Table I:

1 A. S. T. M. Designation 937-49T.

2 A. S. T. M. Designation D127-49.

3 Determined in accordance With Specification MIL-O-11796A. In this test, panels were coated with a -55 mm. film and heated for 3 hours at 130 Any flow during this period of heating fails in this test. 75

,..It Will..be. .seen.;.;frpm.Tahlel. above that it was -im- PQISsible to prepare. a.,satisfact0IY l strpreventiye composition with a base consisting .solely ,of..the.base.oih and. any of,,.the, aforementioned. waxes. More .specifically, .itewill be. ,.not ed that compositions containing relatively low percentages of wax failed, in the flow. test .whereas .compositions containin'g'relatively high percentages of wax failed to provide a composition having an A. S. T. M. penetration in the range of about; 200 to 325 mm./ 10.

Inaccordancewith this inventionymetal soap'of high molecular weight fatty;..acid='=wasiadded to oil-wax bases to formulate compositions having "A-.'-; S. T. M.-penetragtions .in the. range -of. 200.10. 325.;mrn./l0,.melting .points above. Frandfflow -points aboye 130"..F. Imthis example, the-metal soap-was added in the=f0rm of a grease (hereinafterreferredtoasgrease-H) which contained about 12 wt. percent ofa combination-of lithium and calcium soaps of animal :fattyr-acidsi The animal fatty acids were commercial acids: obtained :fromwhy- "drolyzed tallow and hadaniodine number of.-jabout.140 anda ,saponification number of about. 200. and had the following approximate composition:

Aeid: Weight-percent Myristic 3.0 Palmitic Stearic "Oleic Linoleic tinued and-thebala-nceof the mineral oilwas-- added withstirring ovenaperiod-ofiabout 1 to 2 hours and the mixture passed: through a high-shear'milling "device at tern peratures below F.

The following hot-dip rust preventive"compositionwas prepared using thebase oil,.wax..A. an'dgreasmfi -imaccordance with,;the present invention:

,TABLE ,II

Composition,,WtniEerceht 1 E A. s. 1*. M. Melting .Flow'@ 1; Penetration, Point, 130 F. BaseOil 'WaxA "'Gfiase' mm'./10' F! 75 20 5 232 158 Pass.

Contains 12% by weight of soap.

1 A. s. '1. M. Designation DQ37491 I A. S. T. M. Designation D127-49.

Determined in accordance with Specification MILC11796A. In this test, panels were coated with a 50-55 mm. film and heated for 4 hours at 130 F. Any flow during this period of heating fails in this test.

It will be noted that the composition shown in Table II had the properties necessary to formulate an acceptable rust preventive composition. Additional blends were prepared to develop the curves shown in Fig. 1. In this drawing, the curve entitled 0.6% Soap refers to those compositions which contained 5 wt. percent of grease H, and the curve entitled 0.24% Soap refers to those blends which contained 2 wt. percent of grease H. Fig. 2 shows the A. S. T. M. penetrations and flow properties of the compositions of Fig. 1. It should be noted that only those compositions shown in Fig. 2 which have fiow temperatures above 130 F. and A. S. T. M. penetrations in the range of about 200 to 325 are acceptable.

7 Other blends in accordance with this invention were prepared utilizing the base oil, wax A and about 0.5% by weight of aluminum stearate.

Hot-dip rust preventive compositions were also prepared in accordance with this invention using the base oil, wax B and grease H as shown below:

TABLE III Composition, Wt. Percent A. S. T. M. Melting Flow Penetration, Point, 130 F. Base Oil Wax B Gfiase min/10 1 F? 65 30 272 152 Pass. 68 30 2 253 150 Pass.

Contains 12 wt. percent of soap.

1 A. S. T. M. Designation D93749T.

A. S. T. M. Designation D127-49.

Determined in accordance with Specification MIL-C-11796A. In this test, panels were coated with a 50-55 mm. fihn and heated for 4 hours at; 130 F. Any flow during this period of heating fails in this test. It will be noted that the compositions in Table III have the required A. S. T. M. penetration, melting point and flow properties to form acceptable rust preventive compositions.

Example 11 Two rust preventive compositions were then prepared utilizing the base oil and wax A with other ingredients. An additive concentrate containing as the active ingredient about 30% by weight of calcium alkyl benzene sulfonate was employed as a corrosion inhibitor. One of the blends also contained phenylalpha naphthylamine as an oxidation inhibitor. Shown below, in Table IV, are the formulations-of these two compositions as well as their critical properties:

Contains 12% Li-Ca soap.

It will be noted that composition I, which does not contain any metal soap of fatty acids, fails in the flow test although its melting point is above 135 F. This would be expected in view of the results shown in Table I of Example I which showed that acceptable rust preventive compositions could not be prepared utilizing purely oilwax bases. On the other hand, composition II, which was formulated in accordance with the present invention, successfully passed the A. S. T. M. penetration, melting point and flow test at 130 F. Composition II also gave excellent results in the JAN-H-792 humidity cabinet test, which test measures the rust protective properties of a given rust preventive composition.

What is claimed is:

1. A hot-dip rust preventive composition comprising: in the range of to wt. percent of a mineral oil having a viscosity in the range of to 300 SUS at 210 F.; in the range of 12 to 18 wt. percent of a microcrystalline wax having a melting point in the range of to 200 F.; in the range of 2.0 to 4.0 wt. percent of a calcium sulfonate; in the range of 0.1 to 1.0 wt. percent of phenyl a-naphthylamine; and in the range of 0.2 to 0.5 wt. percent of the calcium and lithium soaps of fatty acids having in the range of 14 to 18 carbon atoms per molecule, the molar ratio of lithium soap to calcium soap being in the range of 3:1 to 5:1.

2. A soft film hot-dip rust preventive composition consisting of 71.5 wt. percent of a mineral oil having a viscosity of 200 SUS at 210 F. and a pour point of 0 F., 15 wt. percent of a deoiled and recrystallized microcrystalline wax having a melting point of F. and a penetration of 20, 3.0 wt. percent of a grease containing 12 wt. percent of lithium and calcium soaps of fatty acids obtained from hydrolyzed tallow, the molar ratio of lithium soap to calcium soap being about 4 to 1, 10 wt.

percent of a 30% calcium sulfonate in oil concentrate, and 0.5 wt. percent of phenyl-alpha-naphthylamine.

References Cited in the file of this patent UNITED STATES PATENTS 1,472,239 Buell Oct. 30, 1923 2,430,846 Morgan Nov. 11, 1947 2,471,638 McCarthy May 31, 1949 2,595,158 McCue et a1. Apr. 29, 1952 

1. A HOT-DIP REST PREVENTIVE COMPOSITION COMPRISING: IN THE RANGE OF 70 TO 80 WT. PERCENT OF A MINERAL OIL HAVING A VISCOSITY IN THE RANGE OF 150 TO 300 SUS AT 210*F; IN THE RANGE OF 12 TO 18 WT. PERCENT OF A MICROCRYSTALLINE WAX HAVING A MELTING POINT IN THE RANGE OF 170* TO 200*F; IN THE RANGE OF 2.0 TO 4.0 WT. PERCENT OF A CALCIUM SULFONATE; IN THE RANGE OF 0.1 TO 1.0 WT. PERCENT OF PHENYL A-NAPHTHYLAMINE; AND IN THE RANGE OF 0.2 TO 0.5 WT. PERCENT OF THE CALCIUM AND LITHIUM SOAPS OF FATTY ACIDS HAVING IN THE RANGE OF 14 TO 18 CARBONS ATOMS PER MOLECULE, THE MOLAR RATIO OF LITHIUM SOAP TO CALCIUM SOAP BEING IN THE RANGE OF 3:1 TO 5:1. 